The modern conditions of laundry washing, especially in European countries, involve important mechanical agitation in the washing machine thereby promoting the formation of suds in the washing process. It is therefore an essential aspect of modern laundry detergent compositions that they should comprise an efficient suds control system, often referred to also as suds suppressing system.
It is well known in the art that various silicone oils can provide effective suds control, and many prior art documents therefore disclose liquid detergent compositions comprising silicone oils. See for instance U.S. Pat. Nos. 4,798,679, 4,075,118 and EP 150 872.
However, silicone oils suffer a certain number of drawbacks. A major drawback is that the incorporation of silicone oils in liquid detergents may raise physical stability issues as the level of silicone oil is raised. This problem is particularly acute as detergent compositions are formulated which are more concentrated, which is currently the trend in this technical field.
Also, silicone oils are specialty chemicals which are quite expensive. It is therefore an object of the present invention to formulate detergent compositions which have an efficient suds suppressing system, wherein said suds suppressing system comprises a minimal amount of silicone oil.
It has now been found that this object can be met by using a suds suppressing system which comprises a mixture of a silicone oil and a 2-alkyl-alcanol.
2-alkyl-alcanols have been described in DE 40 21 265 as suds suppressors in detergent compositions. The present invention is based on the finding that silicone oils and 2-alkyl-alcanols will act in synergy to control suds. This finding allows to formulate detergent compositions which comprise very low levels of silicone oils. In some instances, it has been found that the level of both the silicone oil and the 2-alkyl-alcanol can be reduced by a factor three in a mixed suds control system according to the present invention, compared to the level needed to achieve the same suds control with either ingredient alone.